: The authors propose to collect pedigree information, epidemiologic data and biologic specimens from a multiethnic, population-based series of patients with epithelial ovarian cancer and their female relatives, and store the data in a Family Registry for Ovarian Cancer (FROC). They will collect the data from the large, multiethnic population in a six county region in Northern California covered by the Greater Bay Area Cancer Registry (GBACR). Specific aims include: 1) compare family-history-positive (FHP) and family-history-negative (FHN) ovarian cancer patients with respect to ethnicity, invasiveness and histologic type of tumor, and age at diagnosis; 2) evaluate the prevalence of BRCA1 mutations in all FHP and a sample of FHN probands. Use the results to: a) look for correlations between type-site of mutation and ethnicity, invasiveness and histology of tumor, and the spectrum of cancers in the family; and b) validate algorithms for using demographic and epidemiologic attributes and family history to assign a woman a probability of carrying a mutation. Such algorithms are essential for deciding who will be eligible for expensive BRCA1 testing; 3) perform segregation analyses on the pedigree and epidemiologic data (with and without BRCA1 families); 4) identify in probands a representative population of ovarian cancer patients and in their unaffected relatives a representative population of women at high risk for ovarian cancer that could be a) followed for survival and subsequent cancer incidence in relation to ethnicity, family history and BRCA1 mutations, and b) used in candidate gene association studies. The goal is to provide a registry resource for interdisciplinary etiologic and translational research on ovarian cancer. This proposal complements a similar one from the Fred Hutchison Cancer Center, providing the investigators an opportunity to analyze the combined population-based data from Northern California and Western Washington.